Recent experimental psychology […] suggests that the best leaders — both male and female — seem to have relatively high testosterone, which is linked to decreased fear and increased tolerance for risk and desire to compete, and low cortisol, which is linked to decreased anxiety. Effective leadership is associated with hormone levels, and with this hormone profile, leaders are confident and willing to take risks, but not overly threatened or reactive to stressors. [..]

It turns out these two hormones, testosterone and cortisol, are very touchy, sensitive to social and physical cues and fluctuating a great deal over the course of a single day. As Sandberg mentioned in her book, our research shows that people can change their own hormone levels and behaviors, by “faking it” — by “power posing,” or adopting expansive, open nonverbal postures that are strongly associated with power and dominance across the animal kingdom (imagine standing with hands on hips and feet spread, like Wonder Woman). By holding these postures for just two minutes before entering a high-stress situation, people (both men and women) can increase their testosterone by about 20% and decrease their cortisol by about 25%.